U.S. patent number 11,194,433 [Application Number 16/523,366] was granted by the patent office on 2021-12-07 for touch sensor.
This patent grant is currently assigned to DONGWOO FINE-CHEM CO., LTD.. The grantee listed for this patent is DONGWOO FINE-CHEM CO., LTD.. Invention is credited to Do Hyoung Kwon, Jun Gu Lee, Sung Jin Noh, Sang Jin Park, Han Tae Ryu.
United States Patent |
11,194,433 |
Kwon , et al. |
December 7, 2021 |
Touch sensor
Abstract
An improved touch sensor comprising a first sensing electrode
unit formed on a substrate in a first direction and a second
sensing electrode unit formed on the substrate in a second
direction crossing the first direction. A plurality of fine etching
patterns are formed in boundary portions of unit transparent
electrodes included in the first sensing electrode unit and the
second sensing electrode unit. Each unit transparent electrode may
have a shape in which a portion of a curved line connecting the
vertices of a polygon is removed. Adjacent unit transparent
electrodes may be electrically connected to one another. The
improved touch sensor prevents a transparent electrode from being
visible to a user sensor and also results in the prevention of a
reduction in light transmittance caused by the transparent
electrode as well as the prevention a reduction in optical quality
due to a moire phenomenon.
Inventors: |
Kwon; Do Hyoung (Osan-si,
KR), Noh; Sung Jin (Hwaseong-si, KR), Park;
Sang Jin (Pyeongtaek-si, KR), Ryu; Han Tae
(Osan-si, KR), Lee; Jun Gu (Suwon-si, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
DONGWOO FINE-CHEM CO., LTD. |
Iksan-si |
N/A |
KR |
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Assignee: |
DONGWOO FINE-CHEM CO., LTD.
(Jeollabuk-Do, KR)
|
Family
ID: |
1000005977293 |
Appl.
No.: |
16/523,366 |
Filed: |
July 26, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200042141 A1 |
Feb 6, 2020 |
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Foreign Application Priority Data
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Aug 2, 2018 [KR] |
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10-2018-0090160 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F
3/0446 (20190501); G06F 3/0448 (20190501); G06F
2203/04111 (20130101) |
Current International
Class: |
G06F
3/044 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2014-0051649 |
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May 2014 |
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KR |
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2016-0116495 |
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Oct 2016 |
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KR |
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Other References
Notice of Grounds for Rejection issued in counterpart Korean Patent
Appln. No. 10-2018-0090160 dated Nov. 22, 2018, and its English
translation. cited by applicant.
|
Primary Examiner: Lamb; Christopher R
Attorney, Agent or Firm: DLA Piper LLP (US)
Claims
The invention claimed is:
1. A touch sensor comprising: a first sensing electrode unit formed
on a substrate in a first direction; and a second sensing electrode
unit formed on the substrate in a second direction crossing the
first direction, wherein, a plurality of fine etching patterns are
formed in boundary portions of unit transparent electrodes included
in the first sensing electrode unit and the second sensing
electrode unit, each unit transparent electrode has a shape in
which a portion of a curved line connecting vertices of a polygon
is removed, and adjacent unit transparent electrodes are
electrically connected to each other, an inter-electrode dummy is
formed between the first sensing electrode unit and the second
sensing electrode unit, the inter-electrode dummy has the same
shape as the unit transparent electrodes, and the inter-electrode
dummy is electrically insulated from the unit transparent
electrodes, and a plurality of the unit transparent electrodes
distinguished by the fine etching patterns have a tessellation
structure.
2. The touch sensor of claim 1, wherein the curved line is a curved
line that continuously connects the vertices of the polygon or a
curved line that is partially formed by discontinuously connecting
the vertices of the polygon.
3. The touch sensor of claim 1, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among six vertices
of a hexagon is removed.
4. The touch sensor of claim 1, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among four vertices
of a quadrangle arranged in a lattice structure is removed.
5. The touch sensor of claim 1, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among four vertices
of a quadrangle arranged in a zigzag structure is removed.
6. The touch sensor of claim 1, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among four vertices
of a rhombus is removed.
7. The touch sensor of claim 1, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among three vertices
of a triangle is removed.
8. A touch sensor comprising: first sensing electrode units formed
in a first direction and connected to one another; second sensing
electrode units formed in a second direction crossing the first
direction and separated from one another; and a bridge electrode
unit configured to connect two adjacent second sensing electrodes
to each other with one first sensing electrode unit interposed
therebetween, wherein, a plurality of fine etching patterns are
formed in boundary portions of unit transparent electrodes included
in the first sensing electrode unit and the second sensing
electrode unit, each unit transparent electrode has a shape in
which a portion of a curved line connecting vertices of a polygon
is removed, and adjacent unit transparent electrodes are
electrically connected to each other, an inter-electrode dummy is
formed between the first sensing electrode unit and the second
sensing electrode unit, the inter-electrode dummy has the same
shape as the unit transparent electrodes, and the inter-electrode
dummy is electrically insulated from the unit transparent
electrodes, and a plurality of the unit transparent electrodes
distinguished by the fine etching patterns have a tessellation
structure.
9. The touch sensor of claim 8, wherein the curved line is a curved
line that continuously connects the vertices of the polygon or a
curved line that is partially formed by discontinuously connecting
the vertices of the polygon.
10. The touch sensor of claim 8, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among six vertices
of a hexagon is removed.
11. The touch sensor of claim 8, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among four vertices
of a quadrangle arranged in a lattice structure is removed.
12. The touch sensor of claim 8, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among four vertices
of a quadrangle arranged in a zigzag structure is removed.
13. The touch sensor of claim 8, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among four vertices
of a rhombus is removed.
14. The touch sensor of claim 8, wherein the boundary portions of
the unit transparent electrodes have a shape in which a portion of
a curved line connecting two adjacent vertices among three vertices
of a triangle is removed.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
This U.S. non-provisional patent application claims priority under
35 U.S.C. .sctn. 119 of Korean Patent Application No.
10-2018-0090160 filed on Aug. 2, 2018 in the Korean Patent Office,
the entire contents of which are hereby incorporated by
reference.
BACKGROUND
Technical Field
The present invention relates to a touch sensor. More particularly,
the present invention relates to a touch sensor capable of
preventing a reduction in light transmittance due to a transparent
electrode and a reduction in optical quality due to a moire
phenomenon while preventing a transparent electrode from being
unnecessarily visible to a user due to a difference in optical
characteristics between an electrode region where the transparent
electrode is formed and an inter-electrode region where the
transparent electrode is not formed by forming unit transparent
electrodes distinguished by a plurality of fine etching patterns in
the transparent electrode in order to improve visibility and light
transmittance.
Description of Related Art
A touch sensor is a device that, when a user comes into contact
with an image being displayed on a screen by means of his or her
finger or a touch pen, can detect a touch point in response to the
contact. A touch sensor is produced as a structure mounted on a
display device such as a liquid crystal display (LCD), an organic
light-emitting diode (OLED), and the like.
Generally, such a touch sensor includes a touch sensing region
including transparent electrodes formed in directions crossing each
other as a component for sensing a user's touch operation. The
touch sensing region may be divided into an electrode region where
transparent electrodes exist and an inter-electrode region where no
transparent electrodes exist.
Since the electrode region and the inter-electrode region have
different optical characteristics including transmittance and
reflectance, the electrode region and the inter-electrode region
can be distinguished from each other and thus may be unnecessarily
visible to users.
Also, since the electrode region has a relatively low transmittance
compared to the inter-electrode region, a pattern of the touch
sensor may be visible to users.
Such a conventional problem will be described in detail as
follows.
FIG. 1 is a sectional view of a conventional touch sensor, FIG. 2A
and FIG. 2B are diagrams showing an example upper shape of the
conventional touch sensor disclosed in FIG. 1, and FIG. 3 is a
diagram illustrating a principle in which a transparent electrode
is visible to a user due to a low-frequency component of a spatial
frequency generated by the transparent electrode in the
conventional touch sensor disclosed in FIG. 1. The unit of the
spatial frequency of FIG. 3 is cycle per degree (CPD).
Referring to FIG. 1 to FIG. 3, the conventional touch sensor
includes a first sensing electrode 2 made of indium tin oxide (ITO)
and formed on a substrate 1 in a first direction, a second sensing
electrode 3 made of ITO and formed in a second direction crossing
the first direction, an insulating layer 4 configured to insulate
the first sensing electrode 2 from the second sensing electrode 3,
a bridge pattern 5 made of ITO and configured to connect two such
second sensing electrodes 3, and a device protection layer 6. FIG.
2A shows an example upper shape in which the first sensing
electrode 2 and the second sensing electrode 3 are formed, and FIG.
2B shows an example upper shape in which the bridge pattern 5 is
formed in addition to the first sensing electrode 2 and the second
sensing electrode 3.
For the conventional touch sensor, ITO has differences in optical
characteristics such as transmittance/reflectance,
transparent/reflective color sense, and the like depending on
thickness. Thus, there arises a difference in optical
characteristics between an electrode region where ITO is formed and
an inter-electrode region where no ITO is formed, and transmitted
light and reflected light cause an ITO pattern to be visible to
users.
Also, since ITO with a large pitch and thickness is applied to the
bridge pattern 5 in order to secure channel resistance, the bridge
pattern 5 may be visible to users when external light is emitted to
the touch sensor.
The visibility reduction is mainly caused by a low-frequency
component of a spatial frequency generated by the first sensing
electrode 2, the second sensing electrode 3, and the bridge pattern
5. That is, since the first sensing electrode 2, the second sensing
electrode 3, and the bridge pattern 5 are repeatedly formed in the
touch sensor at regular spatial intervals, the low-frequency
component of the spatial frequency corresponding to the spatial
distribution periodicity of the first sensing electrode 2, the
second sensing electrode 3, and the bridge pattern 5 is reinforced
when external light is emitted to the touch sensor. Thus, ITO
itself included in the first sensing electrode 2, the second
sensing electrode 3, and the bridge pattern 5 and an edge region of
ITO may be unnecessarily visible to users.
Also, when the conventional touch sensor having such a problem is
bonded to a display panel, interference may occur between a pixel
array of the display panel and a pixel array of the touch sensor,
and an optical interference pattern may be exhibited as a moire
pattern. A moire phenomenon, which is a defect different from a
pattern visibility defect of a touch sensor, acts as a cause which
reduces the optical quality of an imaging apparatus due to
exhibition of an undesired two-dimensional spatial frequency form
caused by interference between two arrays.
RELATED ART DOCUMENTS
Patent Documents
Korea Patent Publication No. 10-2014-0051649 (Published on May 2,
2014, entitled "METAL MESH TYPE TOUCH SCREEN PANEL")
SUMMARY
1. Technical Problem
A technical objective of the present invention is to prevent a
transparent electrode from being unnecessarily visible to a user
due to a difference in optical characteristics between an electrode
region where the transparent electrode is formed and an
inter-electrode region where no transparent electrode is formed and
also to prevent a reduction in light transmittance due to the
transparent electrode by forming unit transparent electrodes
distinguished by a plurality of fine etching patterns on the
transparent electrode in order to improve visibility and light
transmittance of the transparent electrode.
Another technical objective of the present invention is to increase
light transmittance of a touch sensor and also to enhance the
visibility of the touch sensor by converting a low-frequency
component of a spatial frequency induced by transparent electrodes
that are repeatedly formed inside the touch sensor at regular
spatial intervals into a high-frequency component that is not
visible to a user by means of unit transparent electrodes
distinguished by a plurality of fine etching patterns formed in
each of the transparent electrodes.
Yet another technical objective of the present invention is to
prevent an optical interference pattern due to interference between
a pixel array of a touch sensor and a pixel array of a display
panel from being exhibited as a moire pattern to prevent a
reduction in optical quality when the touch sensor is bonded to the
display panel.
2. Solution to Problem
A touch sensor according to a first aspect of the present invention
includes a first sensing electrode unit formed on a substrate in a
first direction and a second sensing electrode unit formed on the
substrate in a second direction crossing the first direction,
wherein a plurality of fine etching patterns are formed in boundary
portions of unit transparent electrodes included in the first
sensing electrode unit and the second sensing electrode unit, each
unit transparent electrode has a shape in which a portion of a
curved line connecting vertices of a polygon is removed, and
adjacent unit transparent electrodes are electrically connected to
each other.
A touch sensor according to a second aspect of the present
invention includes first sensing electrode units formed in a first
direction and connected to one another; second sensing electrode
units formed in a second direction crossing the first direction and
separated from one another; and a bridge electrode unit configured
to connect two adjacent second sensing electrodes to each other
with one first sensing electrode unit interposed therebetween,
wherein a plurality of fine etching patterns are formed in boundary
portions of unit transparent electrodes included in the first
sensing electrode unit and the second sensing electrode unit, each
unit transparent electrode has a shape in which a portion of a
curved line connecting vertices of a polygon is removed, and
adjacent unit transparent electrodes are electrically connected to
each other.
A touch sensor according to a third aspect of the present invention
includes first sensing electrode units formed on a substrate and
connected to one another in a first direction; an insulating layer
formed on the substrate where the first sensing electrodes are
formed; and second sensing electrode units formed on the insulating
layer and connected to one another in a second direction crossing
the first direction; wherein a plurality of fine etching patterns
are formed in boundary portions of unit transparent electrodes
included in the first sensing electrode unit and the second sensing
electrode unit, each unit transparent electrode has a shape in
which a portion of a curved line connecting vertices of a polygon
is removed, and adjacent unit transparent electrodes are
electrically connected to each other.
In the touch sensors according to the first to third aspects of the
present invention, a plurality of the unit transparent electrodes
distinguished by the fine etching patterns may have a tessellation
structure.
In the touch sensors according to the first to third aspects of the
present invention, the curved line may include one or more selected
from the group consisting of a sine curve, a cosine curve, a conic
section, a catenary, a curve of pursuit, a cycloid, a trochoid, and
a cardioid.
In the touch sensors according to the first to third aspects of the
present invention, the curved line may be a curved line that
continuously connects the vertices of the polygon or a curved line
that is partially formed by discontinuously connecting the vertices
of the polygon.
In the touch sensors according to the first to third aspects of the
present invention, the boundary portions of the unit transparent
electrodes may have a shape in which a portion of a curved line
connecting two adjacent vertices among six vertices of a hexagon is
removed.
In the touch sensors according to the first to third aspects of the
present invention, the boundary portions of the unit transparent
electrodes may have a shape in which a portion of a curved line
connecting two adjacent vertices among four vertices of a
quadrangle arranged in a lattice structure is removed.
In the touch sensors according to the first to third aspects of the
present invention, the boundary portions of the unit transparent
electrodes may have a shape in which a portion of a curved line
connecting two adjacent vertices among four vertices of a
quadrangle arranged in a zigzag structure is removed.
In the touch sensors according to the first to third aspects of the
present invention, the boundary portions of the unit transparent
electrodes may have a shape in which a portion of a curved line
connecting two adjacent vertices among four vertices of a rhombus
is removed.
In the touch sensors according to the first to third aspects of the
present invention, the boundary portions of the unit transparent
electrodes may have a shape in which a portion of a curved line
connecting two adjacent vertices among three vertices of a triangle
is removed.
In the touch sensors according to the first to third aspects of the
present invention, the unit transparent electrodes may have a pitch
ranging from 100 .mu.m to 500 .mu.m.
In the touch sensors according to the first to third aspects of the
present invention, the fine etching patterns may have a width
ranging from 5 .mu.m to 20 .mu.m.
In the touch sensors according to the first to third aspects of the
present invention, a connection unit configured to connect adjacent
unit transparent electrodes may have a width ranging from 20 .mu.m
to 60 .mu.m.
In the touch sensors according to the first to third aspects of the
present invention, the first sensing electrode unit and the second
sensing electrode unit may have transmittance increased by the
plurality of fine etching patterns formed in the boundary portions
of the unit transparent electrodes.
In the touch sensors according to the first to third aspects of the
present invention, the unit transparent electrodes may be formed by
the plurality of fine etching patterns, the first sensing electrode
unit and the second sensing electrode unit may be distinguished by
being the same shape as that of the fine etching patterns included
in each of the unit transparent electrodes, and a spatial
high-frequency component may be disposed on the front surface of
the touch sensor.
The touch sensors according to the first to third aspects of the
present invention may further include an inter-electrode dummy that
is formed between the first sensing electrode unit and the second
sensing electrode unit and that is electrically insulated from the
unit transparent electrodes, the inter-electrode dummy having the
same shape as the unit transparent electrodes.
In the touch sensors according to the first to third aspects of the
present invention, by inserting a plurality of dummy patterns
having the same spatial frequency as the fine etching patterns into
a space between the first sensing electrode unit and the second
sensing electrode unit to dispose the same high-frequency component
on the front surface of the touch sensor, it is possible to prevent
a touch sensor pattern from being visible due to the same
high-frequency component disposed on the front surface of the touch
sensor.
In the touch sensor according to the second aspect of the present
invention, the bridge electrode unit may have one kind of shape
selected from among a straight line, a curved line, and a dumbbell
shape in which both ends are circular and a middle portion is
formed as a straight line.
In the touch sensor according to the second aspect of the present
invention, the bridge electrode unit may have a width ranging from
2 .mu.m to 10 .mu.m.
In the touch sensor according to the second aspect of the present
invention, the bridge electrode unit may contain indium tin oxide
(ITO) and have a length ranging from 100 .mu.m to 500 .mu.m.
In the touch sensor according to the second aspect of the present
invention, the bridge electrode unit may have a width ranging from
15 .mu.m to 60 .mu.m.
3. Advantageous Effects
According to the present invention, by forming unit transparent
electrodes distinguished by a plurality of fine etching patterns on
a transparent electrode in order to improve visibility and light
transmittance of the transparent electrode, it is possible to
prevent the transparent electrode from being unnecessarily visible
to a user due to a difference in optical characteristics between an
electrode region where the transparent electrode is formed and an
inter-electrode region where no transparent electrode is formed and
also to prevent a reduction in light transmittance due to the
transparent electrode.
Also, by converting a low frequency component of a spatial
frequency induced by transparent electrodes that are repeatedly
formed inside a touch sensor at regular spatial intervals into a
high-frequency component that is not visible to a user by means of
unit transparent electrodes distinguished by a plurality of fine
etching patterns formed in each of the transparent electrode, it is
possible to increase the light transmittance of the touch sensor
and also to enhance the visibility of the touch sensor.
Also, when a touch sensor is bonded to a display panel, it is
possible to prevent an optical interference pattern due to
interference between a pixel array of the touch sensor and a pixel
array of the display panel from being exhibited as a moire pattern
and also to prevent a reduction in optical quality.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a sectional view of a conventional touch sensor;
FIG. 2A and FIG. 2B are diagrams showing example upper shapes of
the conventional touch sensor disclosed in FIG. 1;
FIG. 3 is a diagram illustrating a principle in which a transparent
electrode is visible to a user due to a low-frequency component of
a spatial frequency generated by the transparent electrode in the
conventional touch sensor disclosed in FIG. 1;
FIG. 4 is an example sectional view of a touch sensor according to
a first embodiment of the present invention;
FIG. 5 is an example sectional view of a touch sensor according to
a second embodiment of the present invention;
FIG. 6 is an example sectional view of a touch sensor according to
a third embodiment of the present invention;
FIG. 7A to FIG. 7D are diagrams showing one exemplary planar shape
of a transparent fine pattern included in a first sensing electrode
unit and a second sensing electrode unit according to embodiments
of the present invention;
FIG. 8A to FIG. 8D are diagrams illustrating a process of forming
the transparent fine pattern illustrated in FIG. 7A to FIG. 7D;
FIG. 9A to FIG. 9D are diagrams showing another exemplary planar
shape of the transparent fine pattern included in the first sensing
electrode unit and the second sensing electrode unit according to
embodiments of the present invention;
FIG. 10A to FIG. 10D are diagrams illustrating a process of forming
the transparent fine pattern illustrated in FIG. 9A to FIG. 9D;
FIG. 11A to FIG. 11D are diagrams showing another exemplary planar
shape of a transparent fine pattern included in the first sensing
electrode unit and the second sensing electrode unit according to
embodiments of the present invention;
FIG. 12A to FIG. 12D are diagrams illustrating a process of forming
the transparent fine pattern illustrated in FIG. 11A to FIG.
11D;
FIG. 13A to FIG. 13D are diagrams showing another exemplary planar
shape of the transparent fine pattern included in the first sensing
electrode unit and the second sensing electrode unit according to
embodiments of the present invention;
FIG. 14A to FIG. 14D are diagrams illustrating a process of forming
the transparent fine pattern illustrated in FIG. 13A to FIG. 13D;
and
FIG. 15 is a diagram illustrating a principle in which a
low-frequency component of a spatial frequency generated by a
transparent electrode is converted into a high-frequency component
that is not visible to a user by a plurality of transparent fine
patterns in the touch sensor according to embodiments of the
present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
As specific structural or functional descriptions for the
embodiments according to the concept of the invention disclosed
herein are merely exemplified for purposes of describing the
embodiments according to the concept of the invention, the
embodiments according to the concept of the invention may be
embodied in various forms but are not limited to the embodiments
described herein.
While the embodiments of the present invention are susceptible to
various modifications and alternative forms, specific embodiments
thereof are shown by way of example in the drawings and will herein
be described in detail. It should be understood, however, that
there is no intent to limit the invention to the particular forms
disclosed, but on the contrary, the invention is to cover all
modifications, equivalents, and alternatives falling within the
spirit and scope of the invention.
It will be understood that, although the terms "first," "second,"
etc. may be used herein to describe various elements, these
elements should not be limited by these terms. These terms are only
used to distinguish one element from another. For example, a first
element could be termed a second element, and, similarly, a second
element could be termed a first element without departing from the
scope of the present invention.
It will be understood that when an element is referred to as being
"connected" or "coupled" to another element, it can be directly
connected or coupled to the other element or intervening elements
may be present. In contrast, when an element is referred to as
being "directly connected" or "directly coupled" to another
element, there are no intervening elements present. Other words
used to describe the relationship between elements should be
interpreted in a like fashion (i.e., "between" versus "directly
between," "adjacent" versus "directly adjacent," etc.).
The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a," "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises," "comprising," "includes" and/or
"including," when used herein, specify the presence of stated
features, integers, steps, operations, elements, components, or
groups thereof, but do not preclude the presence or addition of one
or more other features, integers, steps, operations, elements,
components, and/or groups thereof.
Unless otherwise defined, all terms (including technical or
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
As will described below, FIG. 4 is a sectional view illustrating a
first embodiment having an upper bridge structure, FIG. 5 is a
sectional view illustrating a second embodiment having a lower
bridge structure, and FIG. 6 illustrates a third embodiment of a
counter electrode structure which uses no bridge electrode.
First, technical features of the present invention that can be
applied regardless of the stacked structures of the first to third
embodiments will be briefly described as follows.
Regardless of the stacked structures of the first to third
embodiments, the present invention includes a first sensing
electrode unit formed on a substrate in a first direction and a
second sensing electrode unit formed on the substrate in a second
direction crossing the first direction. A plurality of fine etching
patterns are formed in boundary portions of unit transparent
electrodes included in the first sensing electrode unit and the
second sensing electrode unit. Each unit transparent electrode may
have a shape in which a portion of a curved line connecting the
vertices of a polygon is removed. Adjacent unit transparent
electrodes may be electrically connected to one another.
The detailed description of the first to third embodiments can be
applied to the plurality of fine etching patterns and the unit
transparent electrodes distinguished by the fine etching patterns,
and thus a redundant description thereof will be omitted.
FIG. 4 is an example sectional view of a touch sensor according to
a first embodiment of the present invention.
Referring to FIG. 4, the touch sensor according to the first
embodiment of the present invention includes a substrate 10, a
first sensing electrode unit 40-1, a second sensing electrode unit
50-1, an insulating layer 60, a bridge electrode unit 70-1, and a
device protection layer 80. It should be noted that the first
embodiment of the present invention is associated with an upper
bridge structure in which the bridge electrode unit 70-1 is located
over the first sensing electrode unit 40-1 and the second sensing
electrode unit 50-1 and the following second embodiment is
associated with a lower bridge structure.
As will be described later, the main technical features of the
touch sensor according to the first embodiment of the present
invention are that the plurality of fine etching patterns are
formed in the boundary portions of the unit transparent electrodes
included in the first sensing electrode 40-1 and the second sensing
electrode unit 50-1, that each unit transparent electrode has a
shape in which a portion of the curved line connecting the vertices
of the polygon is removed, and that adjacent unit transparent
electrodes are electrically connected to one another.
For example, the plurality of unit transparent electrodes
distinguished by the fine etching patterns may be configured to
have a tessellation structure. More preferably, the plurality of
unit transparent electrodes may be configured to have a regular
tessellation structure. The regular tessellation structure is a
tessellation structure consisting of only one type of regular
polygon.
Also, for example, the curved line may include one or more selected
from the group consisting of a sine curve, a cosine curve, a conic
section, a catenary, a curve of pursuit, a cycloid, a trochoid, and
a cardioid and may be a curved line that continuously connects the
vertices of the polygon or a curved line that is partially formed
by discontinuously connecting the vertices of the polygon.
Referring to FIG. 3, which has been referred to while the problems
of the conventional touch sensor were described, and additionally
referring to FIG. 15, which is a diagram illustrating a principle
in which, in the touch sensor according to the first embodiment of
the present invention, a low-frequency component of a spatial
frequency generated by a transparent electrode is converted into a
high-frequency component which is not visible to a user by a
plurality of fine etching patterns formed in boundary portions of
unit transparent electrodes, the unit transparent electrodes are
formed by the plurality of fine etching patterns, the first sensing
electrode unit 40-1 and the second sensing electrode unit 50-1 are
distinguished by being the same shape as that of the fine etching
patterns included in each unit transparent electrode, and a spatial
high-frequency component is disposed on the front of the touch
sensor. In other words, the plurality of fine etching patterns
formed in the boundary portions of the unit transparent electrodes
included in the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may be repeatedly formed inside the
touch sensor at regular spatial intervals. Also, a low-frequency
component of a spatial frequency induced by the first sensing
electrode unit 40-1 and the second sensing electrode unit 50-1
having a relatively larger pitch than the fine etching patterns may
be converted into a high-frequency component that is not visible to
the user. Thus, it is possible to improve the visibility of the
touch sensor. Also, the total light transmittance of the touch
sensor increases along with an increase in the transmittance of the
first sensing electrode unit 40-1 and the second sensing electrode
unit 50-1 due to the plurality of fine etching patterns formed in
the boundary portions of the unit transparent electrodes. The unit
of the spatial frequency of FIG. 15 is cycle per degree (CPD).
According to embodiments of the present invention, it can be seen
that the minimum value of the spatial frequency is about 60 CPD or
less and the low-frequency component of the spatial frequency
generated by the transparent electrode is converted into a
high-frequency component of at least 60 CPD or greater which is not
visible to the user due to the plurality of fine etching patterns,
which are technical features of the present invention.
Exemplary shapes of the unit transparent electrodes distinguished
by fine etching patterns that may be applied to the touch sensor
according to the first embodiment of the present invention will be
described below.
<First Unit Transparent Electrode 101>
FIG. 7A to FIG. 7D are diagrams showing one exemplary planar shape
of unit transparent electrodes 101 included in the first sensing
electrode unit 40-1 and the second sensing electrode unit 50-1
according to embodiments of the present invention, and FIG. 8A to
FIG. 8D are diagrams illustrating a process of forming the unit
transparent electrodes 101 illustrated in FIG. 7A to FIG. 7D.
Additionally referring to FIG. 7A to FIG. 8D, boundary portions of
the unit transparent electrodes 101 included in the first sensing
electrode unit 40-1 and the second sensing electrode unit 50-1 have
a shape in which a portion of a curved line connecting two adjacent
vertices among the six vertices of a hexagon is etched out and
removed, and the etched and removed portion is a fine etching
pattern.
For example, the unit transparent electrodes 101 distinguished by
such fine etching patterns may have a shape corresponding to the
hexagon, and the plurality of unit transparent electrodes 101
included in the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may have a tessellation structure in
which the hexagon is regularly and repeatedly arranged. More
preferably, the plurality of unit transparent electrodes 101 may
have a regular tessellation structure in which a regular hexagon is
regularly and repeatedly arranged.
FIG. 7A shows a planar shape of the plurality of unit transparent
electrodes 101 distinguished by the fine etching patterns included
in the first sensing electrode unit 40-1. FIG. 7B shows a planar
shape of the plurality of unit transparent electrodes 101
distinguished by the fine etching patterns included in the second
sensing electrode unit 50-1. FIG. 7C shows a planar shape of the
bridge electrode unit 70-1. FIG. 7D shows a planar shape of the
touch sensor including the plurality of unit transparent electrodes
101 included in the first sensing electrode unit 40-1 illustrated
in FIG. 7A, the plurality of unit transparent electrodes 101
included in the second sensing electrode unit 50-1 illustrated in
FIG. 7B, and the bridge electrode unit 70-1 illustrated in FIG.
7C.
For example, as illustrated in FIG. 7A to FIG. 7D, when an
inter-electrode region formed by an interval between the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1 has a large width, an inter-electrode dummy 201 which has the
same shape as the unit transparent electrodes 101 and which is
electrically insulated from the unit transparent electrodes 101
included in the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may be additionally formed. As
disclosed in FIG. 7A to FIG. 7D, the plurality of unit transparent
electrodes 101 included in the first sensing electrode unit 40-1
and the second sensing electrode unit 50-1 are electrically
connected to one another, whereas the inter-electrode dummy 201
present in the inter-electrode region is electrically insulated
from the unit transparent electrodes 101. When the inter-electrode
dummy 201 is utilized, a plurality of dummy patterns having the
same spatial frequency as the fine etching patterns may be inserted
into a space between the first sensing electrode unit 40-1 and the
second sensing electrode unit 50-1 to dispose the same
high-frequency component on the front surface of the touch sensor.
Thus, the same high-frequency component disposed on the front
surface of the touch sensor can prevent a touch sensor pattern from
being visible.
In FIG. 7C, the bridge electrode unit 70-1 is represented as a
dumbbell shape in which both ends are circular and a middle portion
is formed as a straight line. However, this is merely an example,
and the bridge electrode unit 70-1 may be formed as a straight line
or a curved line.
As an example, the bridge electrode unit 70-1 may have a material
containing metal. In this case, the bridge electrode unit 70-1 may
have a length ranging from 100 .mu.m to 500 .mu.m and a width
ranging from 2 .mu.m to 10 .mu.m.
As another example, the bridge electrode unit 70-1 may have a
material containing indium tin oxide (ITO). In this case, the
bridge electrode unit 70-1 may have a length ranging from 100 .mu.m
to 500 .mu.m and a width ranging from 15 .mu.m to 60 .mu.m.
Metal has higher electrical conductivity but lower transparency
than ITO. Thus, by allowing the bridge electrode unit 70-1 to have
a shorter width when the bridge electrode unit 70-1 is made of
metal than when the bridge electrode unit 70-1 is made of ITO, it
is possible to improve the visibility of the touch sensor to which
the bridge electrode unit 70-1 made of metal is applied.
A process of forming the plurality of unit transparent electrodes
101 illustrated in FIG. 7A to FIG. 7D is described with reference
to FIG. 8A to FIG. 8D as follows.
In FIG. 8A and FIG. 8B, for convenience of understanding, ITO is
represented in white, and the etched portion is represented in
black. In FIG. 7A, FIG. 7B, FIG. 7D, FIG. 8C, and FIG. 8D, a black
region indicates ITO, and a white region indicates a portion to be
etched out and removed.
First, referring to FIG. 8A, in order to form one unit transparent
electrode 101, a virtual hexagon represented by a dotted line in
the transparent electrode made of the material such as ITO is
assumed, and two adjacent vertices are connected using a curved
line such as a sinusoidal wave. This process is repeatedly
performed on six vertices. As a result, six curved lines are
connected to one another with respect to one virtual hexagon. It
will be appreciated that this process is performed on all of the
unit transparent electrodes as shown in FIG. 8C.
Next, referring to FIG. 8B, one unit transparent electrode 101 is
formed by partially removing the curved lines connected to one
another. In FIG. 8B, a white background region indicates ITO, and a
black curved line is a portion to be removed through etching. This
portion is a fine etching pattern. This process is performed on all
of the unit transparent electrodes 101 as shown in FIG. 8D.
For example, the unit transparent electrodes 101 may have a pitch P
ranging from 100 .mu.m to 500 .mu.m and an interval (i.e., the
width D of the fine etching patterns) ranging from 5 .mu.m to 20
.mu.m. With such a configuration, when external light is applied to
the touch sensor, a low-frequency component of a spatial frequency
induced by the transparent electrode is converted into a
high-frequency component that is not visible to a user, and also
the total light transmittance of the touch sensor increases along
with an increase in the light transmittance of the electrode
region, which is a region where the transparent electrode is
present, i.e., the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1.
Also, for example, a connection unit configured to connect adjacent
unit transparent electrodes 101 may have a width A ranging from 20
.mu.m to 60 .mu.m. With such a configuration, it is possible to
prevent an increase in resistance that may occur during a process
of connecting adjacent unit transparent electrodes 101 and also
prevent a reduction in visibility caused by the connection
unit.
<Second Unit Transparent Electrode 102>
FIG. 9A to FIG. 9D are diagrams showing another exemplary planar
shape of unit transparent electrodes 102 included in the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1 according to embodiments of the present invention, and FIG.
10A to FIG. 10D are diagrams illustrating a process of forming the
unit transparent electrodes 102 illustrated in FIG. 9A to FIG.
9D.
Additionally referring to FIG. 9A to FIG. 10D, boundary portions of
the unit transparent electrodes 102 included in the first sensing
electrode unit 40-1 and the second sensing electrode unit 50-1 have
a shape in which a portion of a curved line connecting two adjacent
vertices among the four vertices of a quadrangle arranged in a
lattice structure is etched out and removed, and the etched and
removed portion is a fine etching pattern.
For example, the unit transparent electrodes 102 distinguished by
such fine etching patterns may have a shape corresponding to the
quadrangle, and the plurality of unit transparent electrodes 102
included in the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may have a tessellation structure in
which the quadrangle is regularly and repeatedly arranged. More
preferably, the plurality of unit transparent electrodes 102 may
have a regular tessellation structure in which a regular quadrangle
is regularly and repeatedly arranged.
FIG. 9A shows a planar shape of the plurality of unit transparent
electrodes 102 distinguished by the fine etching patterns included
in the first sensing electrode unit 40-1. FIG. 9B shows a planar
shape of the plurality of unit transparent electrodes 102
distinguished by the fine etching patterns included in the second
sensing electrode unit 50-1. FIG. 9C shows a planar shape of the
bridge electrode unit 70-1. FIG. 9D shows a planar shape of the
touch sensor including the plurality of unit transparent electrodes
102 included in the first sensing electrode unit 40-1 illustrated
in FIG. 9A, the plurality of unit transparent electrodes 102
included in the second sensing electrode unit 50-1 illustrated in
FIG. 9B, and the bridge electrode unit 70-1 illustrated in FIG.
9C.
For example, as illustrated in FIG. 9A to FIG. 9D, when an
inter-electrode region formed by an interval between the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1 has a large width, an inter-electrode dummy 202 which has the
same shape as the unit transparent electrodes 102 and which is
electrically insulated from the unit transparent electrodes 102
included in the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may be additionally formed. As
disclosed in FIG. 9A to FIG. 9D, the plurality of unit transparent
electrodes 102 included in the first sensing electrode unit 40-1
and the second sensing electrode unit 50-1 are electrically
connected to one another, whereas the inter-electrode dummy 202
present in the inter-electrode region is electrically insulated
from the unit transparent electrodes 102. When the inter-electrode
dummy 202 is utilized, a plurality of dummy patterns having the
same spatial frequency as the fine etching patterns may be inserted
into a space between the first sensing electrode unit 40-1 and the
second sensing electrode unit 50-1 to dispose the same
high-frequency component on the front surface of the touch sensor.
Thus, it is possible to prevent a touch sensor pattern from being
visible by means of the same high-frequency component disposed on
the front surface of the touch sensor.
In FIG. 9C, the bridge electrode unit 70-1 is represented as a
dumbbell shape in which both ends are circular and a middle portion
is formed as a straight line. However, this is merely an example,
and the bridge electrode unit 70-1 may be a straight line or a
curved line.
As an example, the bridge electrode unit 70-1 may have a material
containing metal. In this case, the bridge electrode unit 70-1 may
have a length ranging from 100 .mu.m to 500 .mu.m and a width
ranging from 2 .mu.m to 10 .mu.m.
As another example, the bridge electrode unit 70-1 may have a
material containing ITO. In this case, the bridge electrode unit
70-1 may have a length ranging from 100 .mu.m to 500 .mu.m and a
width ranging from 15 .mu.m to 60 .mu.m.
Metal has higher electrical conductivity but lower transparency
than ITO. Thus, by allowing the bridge electrode unit 70-1 to have
a shorter width when the bridge electrode unit 70-1 is made of
metal than when the bridge electrode unit 70-1 is made of ITO, it
is possible to improve the visibility of the touch sensor to which
the bridge electrode unit 70-1 made of metal is applied.
A process of forming the plurality of unit transparent electrodes
102 illustrated in FIG. 9A to FIG. 9D is described with reference
to FIG. 10A to FIG. 10D as follows.
In FIG. 10A and FIG. 10B, for convenience of understanding, ITO is
represented in white, and the etched portion is represented in
black. In FIG. 9A, FIG. 9B, FIG. 9D, FIG. 10C, and FIG. 10D, a
black region indicates ITO, and a white region indicates a portion
to be etched out and removed.
First, referring to FIG. 10A, in order to form one unit transparent
electrode 102, a virtual quadrangle represented by a dotted line in
the transparent electrode made of the material such as ITO is
assumed, and two adjacent vertices are connected using a curved
line such as a sinusoidal wave. This process is repeatedly
performed on four vertices. As a result, four curved lines are
connected to one another with respect to one virtual quadrangle. It
will be appreciated that this process is performed on all of the
unit transparent electrodes 102 as shown in FIG. 10C.
Next, referring to FIG. 10B, one unit transparent electrode 102 is
formed by partially removing the curved lines connected to one
another. In FIG. 10B, a white background region indicates ITO, and
a black curved line is a portion to be removed through etching.
This portion is a fine etching pattern. This process is performed
on all of the unit transparent electrodes 102 as shown in FIG.
10D.
For example, the unit transparent electrodes 102 may have a pitch P
ranging from 100 .mu.m to 500 .mu.m and an interval (i.e., the
width D of the fine etching patterns) ranging from 5 .mu.m to 20
.mu.m. With such a configuration, when external light is applied to
the touch sensor, a low-frequency component of a spatial frequency
induced by the transparent electrode is converted into a
high-frequency component that is not visible to a user, and also
the total light transmittance of the touch sensor increases along
with an increase in the light transmittance of the electrode
region, which is a region where the transparent electrode is
present, i.e., the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1.
Also, for example, a connection unit configured to connect adjacent
unit transparent electrodes 102 may have a width A ranging from 20
.mu.m to 60 .mu.m. With such a configuration, it is possible to
prevent an increase in resistance that may occur during a process
of connecting adjacent unit transparent electrodes 102 and also to
prevent a reduction in visibility caused by the connection
unit.
<Third Unit Transparent Electrode 103>
FIG. 11A to FIG. 11D are diagrams showing another exemplary planar
shape of unit transparent electrodes 103 included in the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1 according to embodiments of the present invention, and FIG.
12A to FIG. 12D are diagrams illustrating a process of forming the
unit transparent electrodes 103 illustrated in FIG. 11A to FIG.
11D.
Additionally referring to FIG. 11A to FIG. 12D, boundary portions
of the unit transparent electrodes 103 included in the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1 have a shape in which a portion of a curved line connecting
two adjacent vertices among the four vertices of a quadrangle
arranged in a zigzag structure is etched out and removed, and the
etched and removed portion is a fine etching pattern.
For example, the unit transparent electrodes 103 distinguished by
such fine etching patterns may have a shape corresponding to the
quadrangle, and the plurality of unit transparent electrodes 103
included in the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may have a tessellation structure in
which the quadrangle is regularly and repeatedly arranged. More
preferably, the plurality of unit transparent electrodes 103 may
have a regular tessellation structure in which a regular quadrangle
is regularly and repeatedly arranged.
FIG. 11A shows a planar shape of the plurality of unit transparent
electrodes 103 distinguished by the fine etching patterns included
in the first sensing electrode unit 40-1. FIG. 11B shows a planar
shape of the plurality of unit transparent electrodes 103
distinguished by the fine etching patterns included in the second
sensing electrode unit 50-1. FIG. 11C shows a planar shape of the
bridge electrode unit 70-1. FIG. 11D shows a planar shape of the
touch sensor including the plurality of unit transparent electrodes
103 included in the first sensing electrode unit 40-1 illustrated
in FIG. 11A, the plurality of unit transparent electrodes 103
included in the second sensing electrode unit 50-1 illustrated in
FIG. 11B, and the bridge electrode unit 70-1 illustrated in FIG.
11C.
For example, as illustrated in FIG. 11A to FIG. 11D, when an
inter-electrode region formed by an interval between the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1 has a large width, an inter-electrode dummy 203 which has the
same shape as the unit transparent electrodes 103 and which is
electrically insulated from the unit transparent electrodes 103
included in the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may be additionally formed. As
disclosed in FIG. 11A to FIG. 11D, the plurality of unit
transparent electrodes 103 included in the first sensing electrode
unit 40-1 and the second sensing electrode unit 50-1 are
electrically connected to one another, whereas the inter-electrode
dummy 203 present in the inter-electrode region is electrically
insulated from the unit transparent electrodes 103. When the
inter-electrode dummy 203 is utilized, a plurality of dummy
patterns having the same spatial frequency as the fine etching
patterns may be inserted into a space between the first sensing
electrode unit 40-1 and the second sensing electrode unit 50-1 to
dispose the same high-frequency component on the front surface of
the touch sensor. Thus, it is possible to prevent a touch sensor
pattern from being visible by means of the same high-frequency
component disposed on the front surface of the touch sensor.
In FIG. 11C, the bridge electrode unit 70-1 is represented as a
dumbbell shape in which both ends are circular and a middle portion
is formed as a straight line. However, this is merely an example,
and the bridge electrode unit 70-1 may be a straight line or a
curved line.
As an example, the bridge electrode unit 70-1 may have a material
containing metal. In this case, the bridge electrode unit 70-1 may
have a length ranging from 100 .mu.m to 500 .mu.m and a width
ranging from 2 .mu.m to 10 .mu.m.
As another example, the bridge electrode unit 70-1 may have a
material containing ITO. In this case, the bridge electrode unit
70-1 may have a length ranging from 100 .mu.m to 500 .mu.m and a
width ranging from 15 .mu.m to 60 .mu.m.
Metal has higher electrical conductivity but lower transparency
than ITO. Thus, by allowing the bridge electrode unit 70-1 to have
a shorter width when the bridge electrode unit 70-1 is made of
metal than when the bridge electrode unit 70-1 is made of ITO, it
is possible to improve the visibility of the touch sensor to which
the bridge electrode unit 70-1 made of metal is applied.
A process of forming the plurality of unit transparent electrodes
103 illustrated in FIG. 11A to FIG. 11D is described with reference
to FIG. 12A to FIG. 12D as follows.
In FIG. 12A and FIG. 12B, for convenience of understanding, ITO is
represented in white, and the etched portion is represented in
black. In FIG. 11A, FIG. 11B, FIG. 11D, FIG. 12C, and FIG. 12D, a
black region indicates ITO, and a white region indicates a portion
to be etched out and removed.
First, referring to FIG. 12A, in order to form one unit transparent
electrode 103, it is assumed that a virtual quadrangle represented
by a dotted line in the transparent electrode made of the material
such as ITO is arranged in a zigzag structure, and two adjacent
vertices of the virtual quadrangle are connected using a curved
line such as a sinusoidal wave. This process is repeatedly
performed on four vertices. As a result, four curved lines are
connected to one another with respect to one virtual quadrangle. It
will be appreciated that this process is performed on all of the
unit transparent electrodes 103 as shown in FIG. 12C.
Next, referring to FIG. 12B, one unit transparent electrode 103 is
formed by partially removing the curved lines connected to one
another. In FIG. 12B, a white background region indicates ITO, and
a black curved line is a portion to be removed through etching.
This portion is a fine etching pattern. This process is performed
on all of the unit transparent electrodes 103 as shown in FIG.
12D.
For example, the unit transparent electrodes 103 may have a pitch P
ranging from 100 .mu.m to 500 .mu.m and an interval (i.e., the
width D of the fine etching patterns) ranging from 5 .mu.m to 20
.mu.m. With such a configuration, when external light is applied to
the touch sensor, a low-frequency component of a spatial frequency
induced by the transparent electrode is converted into a
high-frequency component that is not visible to a user, and also
the total light transmittance of the touch sensor increases along
with an increase in the light transmittance of the electrode
region, which is a region where the transparent electrode is
present, i.e., the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1.
Also, for example, a connection unit configured to connect adjacent
unit transparent electrodes 103 may have a width A ranging from 20
.mu.m to 60 .mu.m. With such a configuration, it is possible to
prevent an increase in resistance that may occur during a process
of connecting adjacent unit transparent electrodes 103 and also to
prevent a reduction in visibility caused by the connection
unit.
<Fourth Unit Transparent Electrode 104>
FIG. 13A to FIG. 13D are diagrams showing another exemplary planar
shape of unit transparent electrodes 104 included in the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1 according to embodiments of the present invention, and FIG.
14A to FIG. 14D are diagrams illustrating a process of forming the
unit transparent electrodes 104 illustrated in FIG. 13A to FIG.
13D.
Additionally referring to FIG. 13A to FIG. 14D, boundary portions
of the unit transparent electrodes 104 included in the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1 have a shape in which a portion of a curved line connecting
two adjacent vertices among the four vertices of a rhombus is
etched out and removed, and the etched and removed portion is a
fine etching pattern.
For example, the unit transparent electrodes 104 distinguished by
such fine etching patterns may have a shape corresponding to the
rhombus, and a plurality of unit transparent electrodes 104
included in the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may have a tessellation structure in
which the rhombus is regularly and repeatedly arranged. More
preferably, the plurality of unit transparent electrodes 104 may
have a regular tessellation structure.
FIG. 13A shows a planar shape of the plurality of unit transparent
electrodes 104 distinguished by the fine etching patterns included
in the first sensing electrode unit 40-1. FIG. 13B shows a planar
shape of the plurality of unit transparent electrodes 104
distinguished by the fine etching patterns included in the second
sensing electrode unit 50-1. FIG. 13C shows a planar shape of the
bridge electrode unit 70-1. FIG. 13D shows a planar shape of the
touch sensor including the plurality of unit transparent electrodes
104 included in the first sensing electrode unit 40-1 illustrated
in FIG. 13A, the plurality of unit transparent electrodes 104
included in the second sensing electrode unit 50-1 illustrated in
FIG. 13B, and the bridge electrode unit 70-1 illustrated in FIG.
13C.
For example, as illustrated in FIG. 13A to FIG. 13D, when an
inter-electrode region formed by an interval between the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1 has a large width, an inter-electrode dummy 204 which has the
same shape as the unit transparent electrodes 104 and which is
electrically insulated from the unit transparent electrodes 104
included in the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may be additionally formed. As
disclosed in FIG. 13A to FIG. 13D, the plurality of unit
transparent electrodes 104 included in the first sensing electrode
unit 40-1 and the second sensing electrode unit 50-1 are
electrically connected to one another, whereas the inter-electrode
dummy 204 present in the inter-electrode region is electrically
insulated from the unit transparent electrodes 104. When the
inter-electrode dummy 204 is utilized, a plurality of dummy
patterns having the same spatial frequency as the fine etching
patterns may be inserted into a space between the first sensing
electrode unit 40-1 and the second sensing electrode unit 50-1 to
dispose the same high-frequency component on the front surface of
the touch sensor. Thus, it is possible to prevent a touch sensor
pattern from being visible by means of the same high-frequency
component disposed on the front surface of the touch sensor.
In FIG. 13C, the bridge electrode unit 70-1 is represented as a
dumbbell shape in which both ends are circular and a middle portion
is formed as a straight line. However, this is merely an example,
and the bridge electrode unit 70-1 may be a straight line or a
curved line.
As an example, the bridge electrode unit 70-1 may have a material
containing metal. In this case, the bridge electrode unit 70-1 may
have a length ranging from 100 .mu.m to 500 .mu.m and a width
ranging from 2 .mu.m to 10 .mu.m.
As another example, the bridge electrode unit 70-1 may have a
material containing ITO. In this case, the bridge electrode unit
70-1 may have a length ranging from 100 .mu.m to 500 .mu.m and a
width ranging from 15 .mu.m to 60 .mu.m.
Metal has higher electrical conductivity but lower transparency
than ITO. Thus, by allowing the bridge electrode unit 70-1 to have
a shorter width when the bridge electrode unit 70-1 is made of
metal than when the bridge electrode unit 70-1 is made of ITO, it
is possible to improve the visibility of the touch sensor to which
the bridge electrode unit 70-1 made of metal is applied.
A process of forming the plurality of unit transparent electrodes
104 illustrated in FIG. 13A to FIG. 13D is described with reference
to FIG. 14A to FIG. 14D as follows.
In FIG. 14A and FIG. 14B, for convenience of understanding, ITO is
represented in white, and the etched portion is represented in
black. In FIG. 13A, FIG. 13B, FIG. 13D, FIG. 14C, and FIG. 14D, a
black region indicates ITO, and a white region indicates a portion
to be etched out and removed.
First, referring to FIG. 14A, in order to form one unit transparent
electrode 104, a virtual rhombus represented by a dotted line in
the transparent electrode made of the material such as ITO is
assumed, and two adjacent vertices of the virtual rhombus are
connected using a curved line such as a sinusoidal wave. This
process is repeatedly performed on four vertices. As a result, four
curved lines are connected to one another with respect to one
virtual rhombus. It will be appreciated that this process is
performed on all of the unit transparent electrodes 104 as shown in
FIG. 14C.
Next, referring to FIG. 14B, one unit transparent electrode 104 is
formed by partially removing the curved lines connected to one
another. In FIG. 14B, a white background region indicates ITO, and
a black curved line is a portion to be removed through etching.
This portion is a fine etching pattern. This process is performed
on all of the unit transparent electrodes 104 as shown in FIG.
10D.
For example, the unit transparent electrodes 104 may have a pitch P
ranging from 100 .mu.m to 500 .mu.m and an interval (i.e., the
width D of the fine etching patterns) ranging from 5 .mu.m to 20
.mu.m. With such a configuration, when external light is applied to
the touch sensor, a low-frequency component of a spatial frequency
induced by the transparent electrode is converted into a
high-frequency component that is not visible to a user, and also
the total light transmittance of the touch sensor increases along
with an increase in the light transmittance of the electrode
region, which is a region where the transparent electrode is
present, i.e., the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1.
Also, for example, a connection unit configured to connect adjacent
unit transparent electrodes 104 may have a width A ranging from 20
.mu.m to 60 .mu.m. With such a configuration, it is possible to
prevent an increase in resistance that may occur during a process
of connecting adjacent unit transparent electrodes 104 and also to
prevent a reduction in visibility caused by the connection
unit.
Although not shown in a drawing, boundary portions of the unit
transparent electrodes included in the first sensing electrode unit
40-1 and the second sensing electrode unit 50-1 may have a shape in
which a portion of a curved line connecting two adjacent vertices
among the three vertices of a triangle is removed.
Experiments on the improvement of visibility due to the first and
second sensing electrode units, each of which is an aggregation of
the unit transparent electrodes distinguished by the plurality of
fine etching patterns, i.e., experiments on a property in which a
transparent electrode is not unnecessarily visible to a user,
actually depend on the user's visual acuity. The inventors
questioned whether or not a transparent electrode was visible to
100 experimental groups, and as a result, all of the experimental
groups answered that the transparent electrode was not seen.
The following Table 1 shows a result obtained by comparing the
optical characteristics of the related art and the unit transparent
electrodes 101, 102, 103, and 104 having the four patterns of the
first embodiment of the present invention.
TABLE-US-00001 TABLE 1 First Unit Second Unit Third Unit Fourth
Unit Transparent Transparent Transparent Transparent Electrode
Electrode Electrode Electrode Related Art (101) (102) (103) (104)
Transmittance 78.9 79.9 79.8 80 80.7 (%) Reflectance 20.5 19.4 19.5
19.6 18.9 (%) Visibility 10 0 0 0 0 (Maximum: 10)
Referring to Table 1, both of the transmittance and the reflectance
were improved when the unit transparent electrodes 101, 102, 103,
and 104 to which four fine etching patterns were applied were
applied to the first and second sensing electrode units according
to the first embodiment of the present invention as compared to
when the related art in which the transparent fine pattern was not
applied. Also, in the visibility experiment for the experimental
groups, that is, in a question about whether the transparent
electrode was visible, all of the experimental groups answered that
the transparent electrode was not visible.
The elements will be described in detail below.
The substrate 10 is a base that structurally supports the elements
constituting the touch sensor.
As one example, the substrate 10 may be configured to have a rigid
material with excellent properties such as heat resistance and
chemical resistance, for example glass, stainless steel (SUS), and
the like.
As another example, the substrate 10 may be configured to have a
flexible material. With such a configuration, the touch sensor may
be stably applied to a bendable, foldable, rollable, or stretchable
display that requires flexible properties.
For example, the substrate 10 having a flexible material may be a
transparent optical film or a polarizing plate.
As the transparent optical film, a film with high transparency,
mechanical strength, and thermal stability may be used. Specific
examples may include films made of thermoplastic resins, including
polyester-based resins such as polyethylene terephthalate,
polyethylene isophthalate, polyethylene naphthalate, and
polybutylene terephthalate; cellulose-based resins such as
diacetylcellulose and triacetylcellulose; polycarbonate-based
resins; acrylic resins such as polymethyl (meth) acrylate and
polyethyl (meth) acrylate; styrene-based resins such as polystyrene
and acrylonitrile-styrene copolymers; polyolefin-based resins such
as polyethylene, polypropylene, cyclo- or norbornene-structured
polyolefins, and ethylene-propylene copolymers; vinyl
chloride-based resins; amide-based resins such as nylon and
aromatic polyamides; imide-based resins; polyether sulfone-based
resins; sulfone-based resins; polyether ether ketone-based resins;
sulfided polyphenylene-based resins; vinyl alcohol-based resins;
vinylidene chloride-based resins; vinyl butyral-based resins;
allylate-based resins; polyoxymethylene-based resins; and
epoxy-based resins. Also, a film made of a blend consisting of the
thermoplastic resins may be used. Also, a film made of a
thermosetting resin such as (meth) acrylic resins, urethane-based
resins, acrylic urethane-based resins, epoxy-based resins, and
silicon-based resins or a film made of an ultraviolet-curable resin
may be used. The transparent optical film may have a thickness that
is appropriately determined. However, typically, the thickness may
be determined to be in the range of 1 .mu.m to 500 .mu.m in
consideration of thin layer properties, workability such as
strength and handleability, and the like. In particular, it is
preferable that the thickness ranges from 1 .mu.m to 300 .mu.m.
More preferably, the thickness may range from 5 .mu.m to 200
.mu.m.
The transparent optical film may contain one or more suitable types
of additives. Examples of the additives include, for example,
ultraviolet absorbers, antioxidants, lubricants, plasticizers,
release agents, anti-coloring agents, anti-flame agents, nucleating
agents, antistatic agents, pigments, and colorants. The transparent
optical film may have a structure including various functional
layers such as a rigid coating layer, an anti-reflective layer, and
a gas barrier layer on one or both surfaces thereof. The functional
layers are not limited to the above description, and a variety of
other functional layers may be included depending on the desired
use.
Also, if necessary, the transparent optical film may be
surface-treated. Examples of the surface treatment may include
drying treatment such as plasma treatment, corona treatment, and
primer treatment, chemical treatment such as alkali treatment
including saponification, etc.
Also, the transparent optical film may be an isotropic film, a
retardation film, or a protective film.
In the case of the isotropic film, an in-plane retardation Ro
(Ro=[(nx-ny).times.d], where nx and ny are each a main refractive
index in a film plan) is less than or equal to 40 nm and preferably
less than or equal to 15 nm, and a thickness-direction retardation
Rth (Rth=[(nx+ny)/2-nz].times.d, where nx and ny are each a main
refractive index in a film plane, nz is a refractive index in a
film thickness direction, and d is a film thickness) ranges from
-90 nm to +75 nm, preferably from -80 nm to +60 nm, and more
preferably from -70 nm to +45 nm.
The retardation film is a film that is manufactured by uni-axial
stretching, bi-axial stretching, polymer coating, and liquid
crystal coating for a polymer film. Generally, the retardation film
is used to enhance and adjust optical properties of a display, such
as viewing angle compensation, color impression improvement, light
leakage improvement, and color adjustment. The retardation film may
include a half-wavelength (1/2) or quarter-wavelength (1/4) plate,
a positive C-plate, a negative C-plate, a positive A-plate, a
negative A-plate, and a biaxial wavelength plate.
The protective film may be a polymer resin film including an
adhesive layer on at least one surface or a self-adhesive film such
as polypropylene. The protective film may be used for protection of
a touch sensor surface and for improvement of processability.
A well-known polarizing plate used for a display panel may be used
as the polarizing plate. Specifically, the polarizing plate may be
formed by stretching a polyvinyl alcohol film and installing a
protective layer on at least one surface of a polarizer dyed with
iodine or a dichroic dye, by orienting a liquid crystal to have
polarizer performance, or by coating a transparent film with an
oriented resin such as polyvinyl alcohol and then stretching and
dying the coated transparent film. However, the present invention
is not limited thereto.
A separation layer 20 is an element that may be applied when the
substrate 10 is made of a flexible material. The separation layer
20 is a layer that is formed to detach the elements of the touch
sensor from a rigid carrier substrate on which the elements are
formed during a manufacturing process for the touch sensor. The
elements detached from the carrier substrate may be bonded to a
film type substrate 10 made of a flexible material by a
roll-to-roll method.
The material of the separation layer 20 is not particularly limited
as long as the material satisfies a condition for providing a
certain level of detachment force and transparency. For example,
the separation layer 20 may be made of a polymer such as
polyimide-based polymers, poly vinyl alcohol-based polymers,
polyamic acid-based polymers, polyamide-based polymers,
polyethylene-based polymers, polystyrene-based polymers,
polynorbornene-based polymers, phenylmaleimide copolymer-based
polymers, polyazobenzene-based polymers,
polyphenylenephthalamide-based polymers, polyester-based polymers,
polymethyl methacrylate-based polymers, polyarylate-based polymers,
cinnamate-based polymers, coumarin-based polymers,
phthalimidine-based polymers, chalcone-based polymers, and aromatic
acetylene-based polymers. The polymers may be used alone or in
combination thereof.
The detachment force of the separation layer 20 is not particularly
limited. For example, the detachment force may be in the range of
0.01N/25 mm to 1N/25 mm and preferably in the range of 0.01N/25 mm
to 0.1N/25 mm. When the range is satisfied, the elements of the
touch sensor may be easily detached from the carrier substrate
without residue during the manufacturing process for the touch
sensor, and also it is possible to reduce a curl and cracks caused
by a tension force generated during the detachment.
The thickness of the separation layer 20 is not particularly
limited. For example, the thickness may range from 10 nm to 1,000
nm and preferably from 50 nm to 500 nm. When the range is
satisfied, the detachment force may be stable, and a uniform
pattern may be formed.
An inner protective layer 30 is formed on the separation layer 20
and is an optional element that may be omitted if necessary. The
inner protective layer 30 functions to prevent the separation layer
20 from being exposed to an etchant for forming the first sensing
electrode unit 40-1, the second sensing electrode unit 50-1, and
the bridge electrode unit 70-1 during the manufacturing process for
the touch sensor according to embodiments of the present
invention.
As the material of the inner protective layer 30, polymers known in
the art may be used with limitation. For example, organic
insulating films may be applied. Among the organic insulating
films, the inner protective layer 30 may be formed of a curable
composition including a polyol and a melamine curing agent, but the
present invention is not limited thereto.
Specific examples of the polyol may include, but are not limited
to, polyether glycol derivatives, polyester glycol derivatives, and
polycaprolactone glycol derivatives.
Specific examples of the melamine curing agent may include, but are
not limited to, methoxy methyl melamine derivatives, methyl
melamine derivatives, butyl melamine derivatives, isobutoxy
melamine derivatives, and butoxy melamine derivatives, and the
like.
As another example, the inner protective layer 30 may be formed of
a hybrid organic-inorganic curable composition. When both of an
organic compound and an inorganic compound are used, it is possible
to reduce a crack generated during a detachment.
The above-described components may be used as the organic compound.
Examples of the inorganic compound include, but are not limited to,
silica-based nanoparticles, silicon-based nanoparticles, glass
nanofibers, and the like.
A plurality of first sensing electrode units 40-1 are formed on a
substrate 10 and connected to one another in a first direction. A
plurality of second sensing electrode units 50-1 are formed on the
substrate 10 and separated from one another in a second direction
crossing the first direction. An insulating layer 60 is formed on
the substrate 10 on which the first sensing electrode units 40-1
and the second sensing electrode units 50-1 are formed such that at
least some of the second sensing electrode units 50-1 are exposed
through a through-hole. A bridge electrode unit 70-1 is formed on
the insulating layer 60 to occupy the through-hole and thus
connects two adjacent second sensing electrode units 50-1 to each
other with a first sensing electrode unit 40-1 interposed
therebetween.
As described above, a plurality of fine etching patterns are formed
in boundary portions of unit transparent electrodes included in the
first sensing electrode units 40-1 and the second sensing electrode
units 50-1. Each unit transparent electrode has a shape in which a
portion of a curved line connecting the vertices of a polygon is
removed, and adjacent unit transparent electrodes are electrically
connected to each other.
The first sensing electrodes units 40-1 are formed in the first
direction while being electrically connected to one another, and
the second sensing electrode units 50-1 are formed in the second
direction while being electrically separated from one another. The
second direction crosses the first direction. For example, the
crossing directions refer to directions of two different straight
lines that are coplanar but not parallel to each other. For
example, the first direction may be an x-axis direction, and the
second direction may be a y-axis direction. Such a first sensing
electrode unit 40-1 and such a second sensing electrode unit 50-1
may be electrically insulated from each other by the insulating
layer 60 which will be described below.
For example, in order to reduce surface resistance, at least one of
the first sensing electrode unit 40-1 and the second sensing
electrode unit 50-1 may have a multi-layer structure, and more
specifically, a triple-layer structure composed of metal oxide,
metal, and metal oxide.
The bridge electrode unit 70-1 electrically connects adjacent
second sensing electrode units 50-1 to each other.
As the first sensing electrode unit 40-1, the second sensing
electrode unit 50-1, and the bridge electrode unit 70-1, any
transparent conductive material may be used without limitation. For
example, the first sensing electrode unit 40-1, the second sensing
electrode unit 50-1, and the bridge electrode unit 70-1 may be
formed of a material selected from among a metal oxide selected
from the group consisting of indium tin oxide (ITO), indium zinc
oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide
(AZO), gallium zinc oxide (GZO), florinthine oxide (FTO), indium
tin oxide-silver-indium tin oxide (ITO-Ag-ITO), indium zinc
oxide-silver-indium zinc oxide (IZO--Ag--IZO), indium zinc tin
oxide-silver-indium zinc tin oxide (IZTO-Ag-IZTO), and aluminum
zinc oxide-silver-aluminum zinc oxide (AZO-Ag-AZO); a metal
selected from the group of gold (Au), silver (Ag), copper (Cu),
molybdenum (Mo), and APC; a nanowire of a metal selected from the
group consisting of gold, silver, copper, and lead; a carbon-based
material selected from the group consisting of carbon nanotubes
(CNT) and graphene; and a conductive polymer material selected from
the group consisting of poly(3,4-ethylenedioxythiophene) (PEDOT)
and polyaniline (PANI). These materials may be used alone or in
combination thereof. Preferably, ITO may be used. Crystalline and
amorphous ITOs are all available.
The thicknesses of the first sensing electrode unit 40-1, the
second sensing electrode unit 50-1, and the bridge electrode unit
70-1 are not particularly limited, but it is preferable that they
are as thin as possible in consideration of the flexibility of the
touch sensor.
Each of the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may be an aggregate of a plurality of
unit transparent electrodes.
For example, the first sensing electrode unit 40-1 and the second
sensing electrode unit 50-1 may independently have polygonal
(triangular, tetragonal, pentagonal, hexagonal, heptagonal, or
more) patterns.
Also, for example, one of the first sensing electrode unit 40-1,
the second sensing electrode unit 50-1, and the bridge electrode
unit 70-1 may be configured in a stripe form.
As the material of the insulating layer 60 for insulating the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1, an insulating material known in the art may be used without
limitation. For example, a thermosetting resin composition or a
photosensitive resin composition including acrylic resins or metal
oxides such as a silicon oxide may be used. Alternatively, the
insulating layer 60 may be formed using an inorganic material such
as a silicon oxide SiOx. In this case, deposition, sputtering, or
the like may be used for the formation.
A device protection layer 80 is formed on the insulating layer 60
on which the bridge electrode unit 70-1 is formed and is configured
to insulate and protect the elements of the touch sensor from the
outside.
As the material of the device protection layer 80, an insulating
material known in the art may be used without limitation. For
example, a thermosetting resin composition or a photosensitive
resin composition including acrylic resins or metal oxides such as
a silicon oxide may be used. Alternatively, the device protection
layer 80 may be formed using an inorganic material such as a
silicon oxide SiOx. In this case, deposition, sputtering, or the
like may be used for the formation.
FIG. 5 is a sectional view of a touch sensor according to a second
embodiment of the present invention.
As described above, while the touch sensor according to the first
embodiment of the present invention has an upper bridge structure
in which the bridge electrode unit 70-1 is located over the first
sensing electrode unit 40-1 and the second sensing electrode unit
50-1, the touch sensor according to the second embodiment of the
present invention has a lower bridge structure in which a bridge
electrode unit 70-2 is located under a first sensing electrode unit
40-2 and a second sensing electrode unit 50-2.
Except for this difference, the second embodiment of the present
invention is substantially the same as the first embodiment, and
thus a redundant description thereof will be omitted.
FIG. 6 is a sectional view of a touch sensor according to a third
embodiment of the present invention.
As described above, unlike the first and second embodiments, the
third embodiment has a counter electrode structure in which no
bridge electrode is used. The counter electrode structure has a
structure in which a first sensing electrode unit 40-3 and a second
sensing electrode unit 50-3 face each other with an insulating
layer 60 interposed therebetween.
Except for this difference, the third embodiment of the present
invention is substantially the same as the first and second
embodiments, and thus a redundant description thereof will be
omitted.
As described above in detail, according to the present invention,
by forming unit transparent electrodes distinguished by a plurality
of fine etching patterns on a transparent electrode in order to
improve visibility and light transmittance of the transparent
electrode, it is possible to prevent the transparent electrode from
being unnecessarily visible to a user due to a difference in
optical characteristics between an electrode region where the
transparent electrode is formed and an inter-electrode region where
no transparent electrode is formed and also to prevent a reduction
in light transmittance due to the transparent electrode.
Also, by converting a low-frequency component of a spatial
frequency induced by transparent electrodes that are repeatedly
formed inside a touch sensor at regular spatial intervals into a
high-frequency component that is not visible to a user by means of
unit transparent electrodes distinguished by a plurality of fine
etching patterns formed in each of the transparent electrodes, it
is possible to increase the light transmittance of the touch sensor
and also to enhance the visibility of the touch sensor.
Also, when a touch sensor is bonded to a display panel, it is
possible to prevent an optical interference pattern due to
interference between a pixel array of the touch sensor and a pixel
array of the display panel from being exhibited as a moire pattern
to prevent a reduction in optical quality.
DESCRIPTION OF SYMBOLS
10: substrate 20: separation layer 30: inner protective layer 40-1,
40-2, 40-3: first sensing electrode unit 50-1, 50-2, 50-3: second
sensing electrode unit 60: insulating layer 70-1, 70-2: bridge
electrode unit 80: device protection layer 101, 102, 103, 104: unit
transparent electrode 201, 202, 203, 204: inter-electrode dummy
* * * * *